Have a urinary tract infection, or bladder infection? Youll probably hear it from every second person you mention it to- “Drink lots of cranberry juice. As much as you can. It really helped me. Cranberry juice.”

Who says? What is this, some kind of folk remedy, an Urban Legend, or has someone actually studied this and found it to work? One man really has looked at this sweet/sour berry, and made it the focus of the last 20 years of his professional life. He has even found the molecule that causes the mythical antibiotic effect.

Professor Itzhak Ofek, a researcher at Tel Aviv University, isolated the molecule, which he named non-dialyzable material or NDM. It seems to coat some bodily surfaces with Teflon-like efficiency, preventing infection-causing agents from taking root., NDM surprisingly appears to have little effect on the good bacteria in our bodies, according to Prof. Ofek.

E. Coli-Proof Proanthocyanidins

In a 1991 paper in the The New England Journal of Medicine [1], he described cranberry juices property of preventing certain E. coli bacteria from sticking to the bladder’s lining. Other fruit juices such as orange, pineapple, guava, mango, and grapefruit did not have the anti-adhesion effect. This followed an earlier 2001 paper in the Federation of American Societies for Experimental Biology Journal [2] in which Rutgers University researchers found that that cranberry proanthocyanidins are absorbed in the body and may possibly be the compounds behind the anti-adhesion of E. coli in the urinary tract.

Women Only

This research, interestingly, only holds true for women. “The whole thing with cranberries seems to be female-oriented,” admits Prof. Ofek.

He continues, “The take-home message is that God created this fruit with a polyphenolic material. We still don’t know its chemical formula, but it seems to target a fraction of bacteria and viruses.” Studies in 2001, 2002 and 2003 focused in women [3] [4] [5], and confirmed the beneficial results. Much of the research has been funded by Ocean Spray Cranberries, Inc.

When you consider that up to 60% of women will experience a urinary tract infection some time in their lives, and a third of them will have several recurrences [6], you start to wonder about the results a little. But dont worry, men, you havent been left out. Recently, it was found that cranberry NDM may also act as an anti-cancer agent, and studies have also looked at cranberries effects as a mouthwash.

“We found that NDM inhibits adhesion of oral bacteria to tooth surfaces and as a consequence reduced the bacterial load that causes cavities in the mouth,” says Prof. Ofek. “And after a clinical trial, we formulated a mouthwash based on cranberries which was patented by Tel Aviv University.”

Prof. Ofek has also collaborated with Dr. Haim Shmuely, physician and lecturer at Tel Aviv University, to find that cranberry also inhibits two-thirds of the “unhealthy” bacteria that clings to gastric cells, which lead to ulcers.

“The results were very interesting”, says Prof. Ofek. “Cranberry helped reduce the load of this bacteria, Helicobacter pylori, in the gut. In combination with antibiotics, it reduced repeat ulcers from approximately 15 percent to about 5 percent.”


  1. Ofek I, Goldhar J, Zafriri D, Lis H, Adar R, Sharon N. Anti-Escherichia coli adhesion activity of cranberry and blueberry juices. New England Journal of Medicine 1991; 324: 1599.

  2. Howell AB, Leahy M, Kurowska E, Guthrie N. In vivo evidence that cranberry proanthocyanidins inhibit adherence of p-fimbriated E. coli bacteria to uroepithelial cells. Federation of American Societies for Experimental Biology Journal 2001; 15: A284.

  3. Kontiokari T, Sundqvist K, Nuutinen M, Pokka T, Koskela M, Uhari M. Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. British Medical Journal 2001; 322: 1571-1575.

  4. June 2002 - Stothers L. A randomized trial to evaluate effectiveness and cost effectiveness of naturopathic cranberry products as prophylaxis against urinary tract infection in women. The Canadian Journal of Urology 2002; 9: 1558-1562.

  5. Kontiokari T, Laitinen J, Jarvi L, Pokka T, Sundqvist K, Uhari M. Dietary factors protecting women from urinary tract infection. American Journal of Clinical Nutrition 2003; 77: 600-604

  6. Foxman B, Barlow R, D’Arcy H, Gillespie B, Sobel JD. Urinary tract infection: self-reported incidence and associated costs. Ann Epidemiol 2000; 10: 509-515

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